Roll supporting means for a rolling mill

ABSTRACT

The disclosure pertains to a rolling mill having balance piston cylinder assemblies arranged in the lower work roll bearing chocks and extending towards and engaging the cooperative bearing chocks of the upper work roll. A supporting pressure for the piston cylinder assemblies is generated by hydrostatic compression of elastomers, self-contained within the cylinders, which material has a prestressed pressure larger than the combined weights of the upper work roll and its chocks which it is designed to support during roll changing of the rolls.

United States Patent [191 Rotter Sept. 18, 1973 ROLL SUPPORTING MEANS FOR A ROLLING MILL [75] Inventor: Friedrich Rotter,

Kreuztal-Kredenhack, Germany [73] Assignee: Siemag Siegener Maschinenbau,

G.m.b.H.

[22] Filed: May 30, 1972 [21] Appl. No.: 257,507

[30] Foreign Application Priority Data June 26, 1971 Germany P 21 31 882.1

[52] 11.5. C1. 72/238 [51] lint. Cl B2lb 31/08 [58] Field of Search 72/238, 239

[56] References Cited UNITED STATES PATENTS 3,541,830 11/1970 Bohnenkamp et a1 72/238 3,589,161 6/1971 Moffett 72/238 Primary Examiner-Milton S. Mehr Attorney-Henry C. Westin [57] ABSTRACT The disclosure pertains to a rolling mill having balance piston cylinder assemblies arranged in the lower work roll bearing chocks and extending towards and engaging the cooperative bearing chocks of the upper work roll. A supporting pressure for the piston cylinder assemblies is generated by hydrostatic compression of elastomers, self-contained within the cylinders, which material has a prestressed pressure larger than the combined weights of the upper work roll and its chocks which it is designed to support during roll changing of the rolls.

7 Claims, 3 Drawing Figures ROLL SUPPORTING MEANS FOR A ROLLING MILL This inventionrelates to a quick work roll change mechanism for a rolling mill stand, whereby the work rolls are maintained separated during the installing and removing processes, but yet transported as a unit with the top roll and its chocks being supported by the chocks of the bottom roll. In this manner the surfaces of the work rolls do not come into contact with each other, thereby avoiding marking when installed in or removed from the mill stand.

In the past the maintenance of a distance between the rolls was attained during the installing and removing process by manually inserted spacers between the opposed surfaces of the chocks in such a manner that the surfaces of the work rolls were spaced from each other and the chocks of the upper roll were firmly supported on the chocks of the bottom roll.

For the same purpose it has been proposed to provide the chocks of the work rolls with projections or extensions on their surfaces facing each other, which during the normal rolling operation are capable of projecting into pocket-like indentations of the other corresponding chock. In the installing or removing of the set of work rolls, the upper work roll with its chocks is raised to such an extent that the projections are completely withdrawn from the pocket-like indentations. The bottom roll with its chocks is then slightly displaced laterally parallel to its longitudinal axis before the upper work roll with its chocks is lowered. In lowering, the projections of the upper chocks touch down on a flat surface of the other chock located sideways to the pocket-like indentations to bring about, on the one hand, a maintenance of distance between the surfaces of both work rolls, and on the other hand, the firm support of the upper work roll with its chocks by the chocks of the bottom roll.

A disadvantage of both of these known work roll quick-change mechanisms is found in that the necessary firm support of the upper work roll with its chocks by the chocks of the bottom work roll required during the installing and removing process of work rolls can only be attained by additional manipulations which result, as a consequence, in considerable delays during the roll changing and, consequently, a corresponding shortening of the production period.

The object of the present invention is to provide a construction for the work rolls quick-change mechanisms for roll stands which will during the installing and removing process of a set of work rolls automatically maintain at a distance the surfaces of the work rolls effecting, thereby, a firm support of the upper work rolls with its chocks by the chocks of the bottom work roll.

In accordance with the invention the solution of this object consists firstly in that the supporting components of the chocks are constructed as prestressed cushions of hydrostatic compressionof elastomers whose common initial working or supporting force is larger than the weight of a work roll with its chocks.

Such prestressed cushions working with an hydrostatic compression of elastomers are available to the trade under the trade name of JARRET manufactured by Domange-Jarret of Paris, France, who is also represented by Rotator Products Ltd., 464 McNicoll Ave., Willowdale, Ontario, Canada. These cushions or force limiters can be provided with a high initial stress or energy through the internal initial pressure of the elastomer which, in accordance with the invention, is utilized to support the weight of the upper work roll with its chocks; thus, lifting the surfaces of the work rolls from each other and creating thereby an automatic firm support of the upper work roll with its chocks by the chocks of the bottom work roll. But, on the other hand, the prestressing of these cushions or force limiters can be easily overcome by the screwdown devices of the roll stands. Therefore, in accordance with the invention, there are no longer required any additional manipulations in order to assure during the installing and removing process a firm support of the upper work roll with its chocks by the chocks of the bottom work roll.

A further characteristic of the invention is that the cushions or force limiters are installed in the plungers of the work roll balance piston cylinder assemblies of the mill.

Further, in accordance with the invention, the cushions or force limiters can consist of a self-contained cylinder containing an elastomer and a plunger piston penetrating into the elastomer.

Finally, another characteristic of the invention is that the plunger pistons of the cushions or force limiters include a mechanical detent, at least for their extended final position. In this way it is assured that all cushions or force limiters rest at a same level in their extended final position creating thus a firm support for the set of work rolls.

In order to attain an assured support of the upper work roll chocks by the bottom work roll chocks, it is provided, in accordance with the invention, that the plungers of the work roll balance piston cylinder assemblies engage with centering disks located in indentations of the upper work roll chocks.

A preferred form of. the invention is represented in the accompanying drawing in which there is illustrated FIG. 1 a partial sectional side view of the roll assem bly supporting mechanism in which the rolls and mechanism are shown in their roll changing positions;

FIG. 2 an enlarged view of one of the supporting mechanisms shown in FIG. 1; and

FIG. 3 a view similar to FIG. 2, but illustrating the position of the supporting mechanism during the rolling operation.

In FIG. 1 there is shown an indication of one of two housings 1 of a roll stand'in whose windowZ there is supported a chock 3 for the upper work roll 4 and a chock 5 for the bottom work roll 6, according to wellknown practice. A similar chock arrangement, while not shown, will be provided for the other housing. As is customary, the set of work rolls 4, 6 together with its chocks 3, S are designed to be removed from and installed with the windows of the housings for the purpose of roll changing in which the rolls, as a unit, are axially moved relative to the roll stand 1. During the process of removing or installing of the work roll sets, the upper work roll chocks 3 are supported on the bottom work roll chocks 5 at such a distance that both work rolls 4 and 6 are prevented from touching each other. It is important, as noted previously, that during the changing of the rolls a positively supported and stable work roll set be obtained.

In accordance with the present invention, there are utilized as supporting components between each upper work roll chock 3 and the bottom work roll chock 5 two prestressed cushions 7 of the hydrostatic compression of elastomer type which, as noted before, are available on the market as JARRET springs, stress limiters or buffers.

Each of these cushions consists of a self-contained cylinder 8, in which there is positioned an elastomer 9, and of a plunger piston 10 arranged to penetrate into the elastomer 9. Elastomers, as is well known, belong to a large family of macromolecular materials having a wide range of elasticity, that is to say, an important elastic recovery and at the same time an exceptional aptitude for deformation. These natural, organic or synthetic materials have a putty-like consistency and are capable, therefore, of being displaced to a certain extent in a liquid manner during the penetration of the plunger piston 10 into the cylinder 8 due to the effect of the compression created by the piston.

In accordance with the present invention the elastomer 9 is positioned in the cylinder 8 under such an initial stress that it tends to maintain the plunger piston 10 with substantial force at the bottom of the cylinder 8 as indicated in FIG. 2. This common initial stress force of the elastomer 9 in all four cylinders 8 of the four chocks is greater than the net weight of the upper work roll 4 and both of its chocks 3. Due to the initial stress of the elastomers 9 in the cylinders 8, the upper work roll 4 with both of its chocks 3 is therefore completely and automatically lifted away from the bottom work roll 6 and both of its chocks 5 until the lower piston surfaces 11 of the plunger pistons 10 mechanically rest against the lower ends 12 of the cylinders 8 which serve as detents. Thus, a firm position for the set of work rolls is assured during the installing and removing process.

The initial stress force of the elastomer 9 in the cylinders 8 can, however, be overcome by means of the well-known screwdown devices of the roll stands during the rolling operation, the lowering of the upper roll 4 by causing each of the plunger pistons 11 to penetrate deeper into the elastomer 9 and that the latter flows at a slight increase of the initial stress force along the plunger piston 10 into the lower part of the cylinder 8, as shown in FIG. 3. Subsequent to the raising of the screwdown devices of the roll stand, the increased initial stress force of the elastomer 9 will have the effect of pushing back the plunger piston l into its initial position, as shown in FIG. 2. In this way, not only can both work rolls 4 and 6 with their chocks 3 and be joined again in a firm supporting position for their installing and removing, but a balancing of the upper roll can be effected during rolling.

An especially adequate and simple construction of the work roll quick change mechanism in accordance with the invention is represented in the drawing. In the illustrated form of construction it will be noted that each cylinder 8 of the cushion 7 is mounted in the plunger 13 of the work roll balance piston cylinder assembly which penetrates into the balancing cylinder 14 in the bottom work roll chock 5. In this way, the piston plunger of the cushion 7 is connected to and supported by the bottom of the balancing cylinder 14. The cushions 7 constructed as force limiters or stops also assist during the rolling operation with the balancing of the upper work roll until the piston plunger 10 comes to a rest with its lower piston surface 11 on the lower end of the cylinder 8. Only at this moment is there effected the balancing of the upper work roll 4 in the customary manner by means of the plungers 13 driven by fluid in the balancing cylinders 14.

FIGS. 2 and 3 of the drawing shows that the plungers 13 of the work roll balance are provided with centering disks 15 at their free extremities which snugly fit into adapted indentations 16 of the upper work roll chocks 3. This arrangement is especially adequate during the installing and removing of the sets of work rolls since it exactly positions the upper work roll 4 with its chocks 3 in relation to the chocks 5 of the bottom work roll 6. The special advantage of the work roll quick change mechanism in accordance with the invention is that without additional manipulations subsequent to the raising of the screwdown devices the work rolls 4 and 6 with their chocks 3 and 5 automatically attain their supporting position in regard to each other for the installing and removing of the roll set. A further advantage is that the supporting components, installed to obtain this advantage, can be installed in the work roll balance cylinders and that they can, at least partially, aid in the balancing process for the upper work roll 4.

In accordance with the provisions of the patent statutes, I have explained the principle and operation of my invention and have illustrated and described what I consider to represent the best embodiment thereof.

I claim: 1. In a rolling mill having an upper and lower roll, each being carried by bearing chocks arranged at opposite ends of the rolls, in which the chocks on corresponding ends of the rolls oppose each other and form cooperative pairs,

supporting means carried by the chocks of one of said rolls extending towards said opposite chocks of the other roll for supporting the other roll in a spaced-apart relationship with respect to said one roll during removal and replacement of the rolls to and from the mill,

said supporting means including an hydrostatic compression elastomer having an initial prestressed pressure larger than combined weights of the upper roll and its bearing chocks.

2. In a rolling mill according to claim 1 wherein said supporting means comprises a pair of means for each cooperative pair of chocks and in which said supporting means is arranged in the chocks of said lower roll and adapted to support said upper roll and its chocks.

'3. In a rolling mill according to claim I wherein said mill includes a pair of balance piston cylinder assemblies extending between said opposed chocks,

said supporting means arranged in the pistons of said piston cylinder assemblies and including means functioning as force limiting devices for said supporting means.

4. In a rolling mill according to claim 3 in which each piston cylinder assembly includes an internal cylinder formed in the piston of said piston cylinder assembly into which said internal cylinder said elastomer is received,

a plunger received in said internal cylinder arranged to penetrate said elastomer.

5. In a rolling mill according to claim 4 in which said plunger has an enlarged head, a detent formed on said internal cylinder for engagement by said enlarged head of said plunger.

6. In a rolling mill according to claim 3 in which said upper chocks are provided with indentations and the pistons of said piston cylinder assemblies are provided 6 with centering means for each of said pistons arranged piston thereof towards said opposed chock for the purto be rece'ved by Sam mdemat'ons' pose of balancing the roll associated with said opposed 7. In a rolling mill according to claim 3 wherein said balance piston cylinder assemblies, each include a chamber for receiving pressurized fluid to displace said 5 chock. 

1. In a rolling mill having an upper and lower roll, each being carried by bearing chocks arranged at opposite ends of the rolls, in which the chocks on corresponding ends of the rolls oppose each other and form cooperative pairs, supporting means carried by the chocks of one of said rolls extending towards said opposite chocks of the other roll for supporting the other roll in a spaced-apart relationship with respect to said one roll during removal and replacement of the rolls to and from the mill, said supporting means including an hydrostatic compression elastomer having an initial prestressed pressure larger than combined weights of the upper roll and its bearing chocks.
 2. In a rolling mill according to claim 1 wherein said supporting means comprises a pair of means for each cooperative pair of chocks and in which said supporting means is arranged in the chocks of said lower roll and adapted to support said upper roll and its chocks.
 3. In a rolling mill according to claim 1 wherein said mill includes a pair of balance piston cylinder assemblies extending between said opposed chocks, said supporting means arranged in the pistons of said piston cylinder assemblies and including means functioning as force limiting devices for said supporting means.
 4. In a rolling mill according to claim 3 in which each piston cylinder assembly includes an internal cylinder formed in the piston of said piston cylinder assembly into which said internal cylinder said elastomer is received, a plunger received in said internal cylinder arranged to penetrate said elastomer.
 5. In a rolling mill according to claim 4 in which said plunger has an enlarged head, a detent formed on said internal cylinder for engagement by said enlarged head of said plunger.
 6. In a rolling mill according to claim 3 in which said upper chocks are provided with indentations and the pistons of said piston cylinder assemblies are provided with centering means for each of said pistons arranged to be received by said indentations.
 7. In a rolling mill according to claim 3 wherein said balance piston cylinder assemblies, each include a chamber for receiving pressurized fluid to displace said piston thereof towards said opposed chock for the purpose of balancing the roll associated with said opposed chock. 